The present invention relates to a multiple antenna cellular network. In particular, the invention is used in a cellular communication network to custom configure cell boundaries to accommodate obstacles such as walls, ceilings, floors and buildings, to reduce interference, to improve performance and to improve quality of service.
Standard cellular communication networks are generally divided into geographic cells. Each cell typically contains a central antenna, is circular and overlaps slightly with adjacent cells. Base transceiver station hardware is deployed near each antenna to communicate with mobile stations in that cell. Factors that influence cellular design and the amount of deployed hardware include the number of mobile stations to be serviced in a given area, the operational power levels of the mobile stations and base stations, and the presence or absence of obstacles. Other factors include the type of communication protocol such as time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA), or other type. The transmit power and the communication protocol generally define the size of each cell and how many users each cell can support.
When a cellular network is designed, a specified number of users can be serviced by a specified number of cells and associated hardware including the base transceiver stations. When a mobile station passes from one cell to another, a hand-off is performed to permit the mobile station to communicate with the base transceiver station that receives the strongest signal from the mobile station. However, in some circumstances, signals are blocked by obstacles such as buildings and mountains. To accommodate these obstacles, multi-path signal processing is performed, but it is not successful at all possible locations. To service all locations, additional antennas or repeaters must be deployed to create additional cells or enhance coverage even though no additional capacity may be supported. This type of hardware deployment is not efficient.
Low power cellular networks, such as those designed to service a building, have similar problems. In this case, the obstacles are walls, floors and ceilings. To accommodate these obstacles, additional antennas are deployed to create additional cells. Again, the result is that additional antenna or repeater hardware is deployed without an associated increase in the number of serviced mobile stations. Similarly, this deployment is not efficient.
Hence, one limitation of existing systems is that they require additional antenna or repeater hardware to provide service to mobile stations that move behind an obstacle. This results in a deployment of a large amount of hardware for the purpose of communicating with a statistically small number of mobile stations.
The present invention relates to a multiple antenna cellular network. In particular, the invention is used in a cellular communication network to custom configure cell boundaries to accommodate obstacles such as walls, ceilings, floors and buildings, to reduce interference, to improve performance and to improve quality of service. Exemplary embodiments are provided for use with the Global Systems for Mobile Communication (GSM) protocol and can be applied to other cellular communication and digital technologies.
A multiple antenna cellular network communicates with a mobile station over a plurality of antennas. The antennas are arranged in a plurality of positions to customize a cell or cells. A transceiver is coupled to the antennas and configured to receive inbound information from the mobile station and transmit outbound information to the mobile station. A processor is coupled to the transceiver and configured to decode the inbound information and to encode the outbound information to communicate with the mobile station.
In another embodiment, the antennas are similarly deployed to create a cell or cells. The transmit signal power is continuously varied to improve quality and to move the nulls so that a fixed location user can receive a high quality signal.
Advantages of the invention include improved cell boundary control, reduced interference, fault tolerance and more efficient use of radio resources. Additionally, mobile users will experience improved battery life because of lower mobile station transmit power requirements.